Aseptic tanks are equipment that allow the storage and processing of products in aseptic conditions free from microbiological contamination, especially in the food, beverage, pharmaceutical and biotechnology industries. These tanks are designed in accordance with special engineering rules to ensure maximum product safety, quality and hygienic aspects during the working period. During production, full compliance with both hygienic design rules and international pressure vessel standards must be ensured. In addition, aseptic tanks must be sterilizable and sterilization must be validated.
What is an Aseptic Tank and Why Is It Considered a Pressure Vessel?
An aseptic tank is a container designed to store and preserve products in sterile environments, usually made of 316L stainless steel and its interior is CIP (Clean-in-Place) and SIP (Sterilization-in-Place) compatible.
These tanks are usually:
- To keep the product inside sterile, pressure is applied to them, for example, the upper section is protected by nitrogen gas, and product transfer can be done with sterile compressed air or nitrogen.
- Pressurized steam is applied for sterilization processes.
Therefore, these tanks are evaluated within the scope of the European Union's PED 2014/68/EU (Pressure Equipment Directive) directive and pressure vessel standards such as EN 13445 because they are exposed to internal pressure. Especially since the working pressure exceeds 0.5 bar and is in the gas group, tanks are legally classified as pressure vessels and are subject to engineering, manufacturing and test protocoles within this scope.
Things to Consider in Aseptic Tank Production
1.Material Quality
- The most commonly used material is AISI 316L quality stainless steel, which is resistant to corrosion and high temperature. In addition, depending on the application, it can be manufactured in AISI 304L quality stainless steel.
- Mechanical polishing or electropolishing is applied so that the surface roughness (Ra) on the inner surface is min. ≤ 0.8 μm, and in some aseptic applications, the ≤ is 0.4 μm Ra.
2.Hygienic Welding and Surface Treatments
- All welds made by PAW and/or TIG welding method are smoothed by internal grinding and polishing, and then passivation processes are applied with acidic cleaning (pickling).
- It is of great importance in terms of hygiene that there are no burrs, dead zones or product residues at the welds.
3. CIP and SIP Compatible Design
- Tanks must be cleanable-in-place (CIP) and sterilizable-in-place (SIP).
- Therefore;Attention should be paid to details such as CIP spray head, base slope, nozzle placement, outlets that provide full drainability..
4.Pressure and Vacuum Safety
- Aseptic tanks must be designed to operate under both internal pressure and vacuum.
- That's why equipment such as vacuum breakers and safety valves are critical.
Related Standards
Aseptic tanks should be produced in accordance with the following norms and international standards.
- EHEDG (European Hygienic Engineering & Design Group): European guide to hygienic equipment design.
- 3-A Sanitary Standards: U.S.-based, hygienic production guidelines for the dairy and food industries.
- ASME BPE (Bioprocessing Equipment): Covers topics such as surface treatment, connection, welding for biotechnological equipment.
- EN 13445 and PED 2014/68/EU: European harmonization directives for pressure vessels.
- GMP (Good Manufacturing Practice): Rules on the production environment and process of aseptic tanks, especially in the pharmaceutical and biotechnology sectors.
- FDA compliance: Valid for the US market, the materials and gaskets used must be FDA approved.
RESULT
Aseptic tank design and production requires hygienic process knowledge as well as relevant pressure vessel directive knowledge. In sectors where food safety is at a high level, aseptic tanks are considered one of the most important parts of a process. For this reason, operations such as design, production and assembly should be carried out in accordance with the relevant standards and hygiene rules.